There has been extensive prior art activity in the pursuit of averting the use of on-floor conduits for conveying electrical power and communication lines to floor locations which were not within the original architectural and electrical planning of a facility, such as a multi-floor concrete building. Such on-floor conduits are in the first place aesthetically unpleasant and secondly can give rise to personnel danger, such as by tripping over the same.
While the art has averted these problems in the introduction of flat undercarpet cable installations, the problem remains extant in the use of the conventional discrete wiring systems in place in general in existing buildings and for currently-planned facilities for which the undercarpet approach is not elected.
In the conventional discrete installations, the problem under discussion has been addressed by drilling a passage through the concrete floor and conducting power and/or communication signals from a lower floor to the floor in which a new power and/or communication signal outlet is desired. Electrical safety codes have placed two sanctions on such activity. Firstly, it is essential that the installed transition apparatus not function as a chimney or fire-advancing flue in the event of fire occurrence on the lower floor. Secondly, it is imperative that the transition apparatus not function as a conductive heat channel between floors.
The industry has largely met these requirements through the use of intumescent material in the transition apparatus, such material expanding under fire conditions against the concrete circumscribing the passage to effectively block the pre-existing flue which may have been present in the passage. Further, the art includes structures which have conductive heat blocking members, i.e., synthetic spacers, disposed axially between and separating conductive heat communication between heat conductive members of the apparatus.
Presently known transition apparatus can involve one of two diverse types of pedestals, i.e., the flush-mount pedestal and the low-profile pedestal, the latter protruding upwardly of the floor to an extent and the former being essentially continuous with the floor. The flush-mount pedestal has a disadvantage as against the low profile pedestal in that it is susceptible to entry of floor debris, such as dust, moisture and the like. The art has seen various measures taken protectively in this regard, such as sliding, swinging, threaded or other mechanical members to cover the pedestal face. Such measures have evident disadvantage in respect of increased cost of manufacture of the installation and labor intensity in use.